Properties

Label 2.0.420.1-15.1-a1
Base field \(\Q(\sqrt{-105}) \)
Conductor norm \( 15 \)
CM no
Base change yes
Q-curve yes
Torsion order \( 2 \)
Rank \( 1 \)

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Base field \(\Q(\sqrt{-105}) \)

Generator \(a\), with minimal polynomial \( x^{2} + 105 \); class number \(8\).

Copy content comment:Define the base number field
 
Copy content sage:R.<x> = PolynomialRing(QQ); K.<a> = NumberField(R([105, 0, 1]))
 
Copy content gp:K = nfinit(Polrev([105, 0, 1]));
 
Copy content magma:R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![105, 0, 1]);
 
Copy content oscar:Qx, x = polynomial_ring(QQ); K, a = number_field(Qx([105, 0, 1]))
 

Weierstrass equation

\({y}^2+a{x}{y}+a{y}={x}^3-{x}^2-5091{x}-237810\)
Copy content comment:Define the curve
 
Copy content sage:E = EllipticCurve([K([0,1]),K([-1,0]),K([0,1]),K([-5091,0]),K([-237810,0])])
 
Copy content gp:E = ellinit([Polrev([0,1]),Polrev([-1,0]),Polrev([0,1]),Polrev([-5091,0]),Polrev([-237810,0])], K);
 
Copy content magma:E := EllipticCurve([K![0,1],K![-1,0],K![0,1],K![-5091,0],K![-237810,0]]);
 
Copy content oscar:E = elliptic_curve([K([0,1]),K([-1,0]),K([0,1]),K([-5091,0]),K([-237810,0])])
 

This is not a global minimal model: it is minimal at all primes except \((7,a)\). No global minimal model exists.

Copy content comment:Test whether it is a global minimal model
 
Copy content sage:E.is_global_minimal_model()
 

Mordell-Weil group structure

\(\Z \oplus \Z/{2}\Z\)

Mordell-Weil generators

$P$$\hat{h}(P)$Order
$\left(\frac{102627}{722} : -\frac{103349}{1444} a + \frac{31906143}{27436} : 1\right)$$7.3929520095534666291222985968518633092$$\infty$
$\left(\frac{405}{4} : -\frac{409}{8} a : 1\right)$$0$$2$

Invariants

Conductor: $\frak{N}$ = \((15,a)\) = \((3,a)\cdot(5,a)\)
Copy content comment:Compute the conductor
 
Copy content sage:E.conductor()
 
Copy content gp:ellglobalred(E)[1]
 
Copy content magma:Conductor(E);
 
Copy content oscar:conductor(E)
 
Conductor norm: $N(\frak{N})$ = \( 15 \) = \(3\cdot5\)
Copy content comment:Compute the norm of the conductor
 
Copy content sage:E.conductor().norm()
 
Copy content gp:idealnorm(K, ellglobalred(E)[1])
 
Copy content magma:Norm(Conductor(E));
 
Copy content oscar:norm(conductor(E))
 
Discriminant: $\Delta$ = $25322018394645$
Discriminant ideal: $(\Delta)$ = \((25322018394645)\) = \((3,a)^{32}\cdot(5,a)^{2}\cdot(7,a)^{12}\)
Copy content comment:Compute the discriminant
 
Copy content sage:E.discriminant()
 
Copy content gp:E.disc
 
Copy content magma:Discriminant(E);
 
Copy content oscar:discriminant(E)
 
Discriminant norm: $N(\Delta)$ = \( 641204615578739742964676025 \) = \(3^{32}\cdot5^{2}\cdot7^{12}\)
Copy content comment:Compute the norm of the discriminant
 
Copy content sage:E.discriminant().norm()
 
Copy content gp:norm(E.disc)
 
Copy content magma:Norm(Discriminant(E));
 
Copy content oscar:norm(discriminant(E))
 
Minimal discriminant: $\frak{D}_{\mathrm{min}}$ = \((215233605)\) = \((3,a)^{32}\cdot(5,a)^{2}\)
Minimal discriminant norm: $N(\frak{D}_{\mathrm{min}})$ = \( 46325504721296025 \) = \(3^{32}\cdot5^{2}\)
j-invariant: $j$ = \( -\frac{147281603041}{215233605} \)
Copy content comment:Compute the j-invariant
 
Copy content sage:E.j_invariant()
 
Copy content gp:E.j
 
Copy content magma:jInvariant(E);
 
Copy content oscar:j_invariant(E)
 
Endomorphism ring: $\mathrm{End}(E)$ = \(\Z\)   
Geometric endomorphism ring: $\mathrm{End}(E_{\overline{\Q}})$ = \(\Z\)    (no potential complex multiplication)
Copy content comment:Test for Complex Multiplication
 
Copy content sage:E.has_cm(), E.cm_discriminant()
 
Copy content magma:HasComplexMultiplication(E);
 
Sato-Tate group: $\mathrm{ST}(E)$ = $\mathrm{SU}(2)$

BSD invariants

Analytic rank: $r_{\mathrm{an}}$= \( 1 \)
Copy content comment:Compute the Mordell-Weil rank
 
Copy content sage:E.rank()
 
Copy content magma:Rank(E);
 
Mordell-Weil rank: $r$ = \(1\)
Regulator: $\mathrm{Reg}(E/K)$ \( 7.3929520095534666291222985968518633092 \)
Néron-Tate Regulator: $\mathrm{Reg}_{\mathrm{NT}}(E/K)$ \( 14.785904019106933258244597193703726618 \)
Global period: $\Omega(E/K)$ \( 1.11785085630876455088337139105612086116 \)
Tamagawa product: $\prod_{\frak{p}}c_{\frak{p}}$= \( 4 \)  =  \(2\cdot2\cdot1\)
Torsion order: $\#E(K)_{\mathrm{tor}}$= \(2\)
Special value: $L^{(r)}(E/K,1)/r!$ \( 3.2260202759957433623105493911976247536 \)
Analytic order of Ш: Ш${}_{\mathrm{an}}$= \( 4 \) (rounded)

BSD formula

$$\begin{aligned}3.226020276 \approx L'(E/K,1) & \overset{?}{=} \frac{ \# ะจ(E/K) \cdot \Omega(E/K) \cdot \mathrm{Reg}_{\mathrm{NT}}(E/K) \cdot \prod_{\mathfrak{p}} c_{\mathfrak{p}} } { \#E(K)_{\mathrm{tor}}^2 \cdot \left|d_K\right|^{1/2} } \\ & \approx \frac{ 4 \cdot 1.117851 \cdot 14.785904 \cdot 4 } { {2^2 \cdot 20.493902} } \\ & \approx 3.226020276 \end{aligned}$$

Local data at primes of bad reduction

Copy content comment:Compute the local reduction data at primes of bad reduction
 
Copy content sage:E.local_data()
 
Copy content magma:LocalInformation(E);
 

This elliptic curve is semistable. There are 2 primes $\frak{p}$ of bad reduction. Primes of good reduction for the curve but which divide the discriminant of the model above (if any) are included.

$\mathfrak{p}$ $N(\mathfrak{p})$ Tamagawa number Kodaira symbol Reduction type Root number \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{N}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathfrak{D}_{\mathrm{min}}\)) \(\mathrm{ord}_{\mathfrak{p}}(\mathrm{den}(j))\)
\((3,a)\) \(3\) \(2\) \(I_{32}\) Non-split multiplicative \(1\) \(1\) \(32\) \(32\)
\((5,a)\) \(5\) \(2\) \(I_{2}\) Non-split multiplicative \(1\) \(1\) \(2\) \(2\)
\((7,a)\) \(7\) \(1\) \(I_0\) Good \(1\) \(0\) \(0\) \(0\)

Galois Representations

The mod \( p \) Galois Representation has maximal image for all primes \( p < 1000 \) except those listed.

prime Image of Galois Representation
\(2\) 2Cs

Isogenies and isogeny class

This curve has non-trivial cyclic isogenies of degree \(d\) for \(d=\) 2, 4, 8 and 16.
Its isogeny class 15.1-a consists of curves linked by isogenies of degrees dividing 16.

Base change

This elliptic curve is a \(\Q\)-curve. It is the base change of the following 2 elliptic curves:

Base field Curve
\(\Q\) 225.b3
\(\Q\) 11760.p3